imagecreatefrompng

(PHP 4, PHP 5)

imagecreatefrompngCreate a new image from file or URL

Description

resource imagecreatefrompng ( string $filename )

imagecreatefrompng() returns an image identifier representing the image obtained from the given filename.

Tip

A URL can be used as a filename with this function if the fopen wrappers have been enabled. See fopen() for more details on how to specify the filename. See the Supported Protocols and Wrappers for links to information about what abilities the various wrappers have, notes on their usage, and information on any predefined variables they may provide.

Parameters

filename

Path to the PNG image.

Return Values

Returns an image resource identifier on success, FALSE on errors.

Examples

Example #1 Example to handle an error during loading of a PNG

<?php
function LoadPNG($imgname)
{
    
/* Attempt to open */
    
$im = @imagecreatefrompng($imgname);

    
/* See if it failed */
    
if(!$im)
    {
        
/* Create a blank image */
        
$im  imagecreatetruecolor(15030);
        
$bgc imagecolorallocate($im255255255);
        
$tc  imagecolorallocate($im000);

        
imagefilledrectangle($im0015030$bgc);

        
/* Output an error message */
        
imagestring($im155'Error loading ' $imgname$tc);
    }

    return 
$im;
}

header('Content-Type: image/png');

$img LoadPNG('bogus.image');

imagepng($img);
imagedestroy($img);
?>

The above example will output something similar to:

imagecreatefrompng() example

Notes

Warning

Windows versions of PHP prior to PHP 4.3.0 do not support access of remote files via this function, even if allow_url_fopen is enabled.

Коментарии

Автор:
If you're trying to load a translucent png-24 image but are finding an absence of transparency (like it's black), you need to enable alpha channel AND save the setting. I'm new to GD and it took me almost two hours to figure this out.

<?php
$imgPng 
imageCreateFromPng($strImagePath);
imageAlphaBlending($imgPngtrue);
imageSaveAlpha($imgPngtrue);

/* Output image to browser */
header("Content-type: image/png");
imagePng($imgPng); 
?>
2004-06-07 07:14:13
http://php5.kiev.ua/manual/ru/function.imagecreatefrompng.html
I had the same problem as jboyd1189 at yahoo dot com but I solve d it allocating more memory dynamically.

Usually the memory_limit var on php.ini is set to 8M. Unfortunately, the required amount of memory to manage a PNG image about 1000x1000 could be bigger !

The approach I used to solve the problem is:

1-Calculate the memory required by the image
2-Set the new memory_limit value 
3-Create the PNG image and thumbnail
4-Restore the original value

1-The following value works for me:
$required_memory = Round($width * $height * $size['bits']);

Note that for JPEG the requirements are not the same:
http://es2.php.net/manual/en/function.imagecreatefromjpeg.php#60241

2-Use somthing like: 
$new_limit=memory_get_usage() + $required_memory;
ini_set("memory_limit", $new_limit);

4-ini_restore ("memory_limit");
2007-02-28 14:23:27
http://php5.kiev.ua/manual/ru/function.imagecreatefrompng.html
When using imagecreatepng with alpha blending you will lose the blending.

To over come this use something like the following
<?php
$dstimage
=imagecreatetruecolor($width,$height);
$srcimage=imagecreatefrompng($src);
imagecopyresampled($dstimage,$srcimage,0,0,0,0$width,$height,$width,$height);
?>
Where $width and $height are the width and height of the $src image.

This will create a true colour image then copy the png image to this true colour image and retain alpha blending.
2009-04-17 18:06:02
http://php5.kiev.ua/manual/ru/function.imagecreatefrompng.html
Because gd and imagick do not support animated PNG (at this moment), i wrote a simple function to determine if given PNG is APNG or not. It does not validate PNG, only checks whenever "acTL" chunk appears before "IDAT" like the specification says: https://wiki.mozilla.org/APNG_Specification

<?php

function is_apng(string $filename): bool
{
   
$f = new \SplFileObject($filename'rb');
   
$header $f->fread(8);
    if (
$header !== "\x89PNG\r\n\x1A\n") {
        return 
false;
    }
    while (!
$f->eof()) {
       
$bytes $f->fread(4);
        if (
strlen($bytes) < 4) {
            return 
false;
        }
       
$length unpack('N'$bytes)[1];
       
$chunkname $f->fread(4);
        switch (
$chunkname) {
            case 
'acTL':
                return 
true;
            case 
'IDAT':
                return 
false;
        }
       
$f->fseek($length 4SEEK_CUR);
    }
    return 
false;
}

?>
2021-08-02 10:58:26
http://php5.kiev.ua/manual/ru/function.imagecreatefrompng.html

    Поддержать сайт на родительском проекте КГБ